refactor(app.js, auth.js): Extract all auth method to individual modules

lib/web/auth/gitlab/index.js

@@ -0,0 +1,36 @@
+'use strict'
+
+const Router = require('express').Router
+const passport = require('passport')
+const GitlabStrategy = require('passport-gitlab2').Strategy
+const config = require('../../../config')
+const response = require('../../../response')
+const {setReturnToFromReferer, passportGeneralCallback} = require('../utils')
+
+let gitlabAuth = module.exports = Router()
+
+passport.use(new GitlabStrategy({
+  baseURL: config.gitlab.baseURL,
+  clientID: config.gitlab.clientID,
+  clientSecret: config.gitlab.clientSecret,
+  scope: config.gitlab.scope,
+  callbackURL: config.serverurl + '/auth/gitlab/callback'
+}, passportGeneralCallback))
+
+gitlabAuth.get('/auth/gitlab', function (req, res, next) {
+  setReturnToFromReferer(req)
+  passport.authenticate('gitlab')(req, res, next)
+})
+
+// gitlab auth callback
+gitlabAuth.get('/auth/gitlab/callback',
+  passport.authenticate('gitlab', {
+    successReturnToOrRedirect: config.serverurl + '/',
+    failureRedirect: config.serverurl + '/'
+  })
+)
+
+if (!config.gitlab.scope || config.gitlab.scope === 'api') {
+  // gitlab callback actions
+  gitlabAuth.get('/auth/gitlab/callback/:noteId/:action', response.gitlabActions)
+}